Cutter foils for dry shaving apparatus

ABSTRACT

A cutter foil for dry shaving apparatus, produced by electrodeposition, and comprising a main portion in which is an area of perforation and an edge zone joined to the main portion by a fold defining an apex extending longitudinally of the foil, a cutter comb constituted by bars extending across the apex and separated from each other by slots likewise extending across the apex, the breadths of the bars being greater than the breadths of the slots, and the bars containing perforations serving to enhance the thickness of the foil produced by electro-deposition in the region of the bars, the perforations in the bars being clear of a zone adjacent to the apex, whereby in each bar the foil is continuous across the width of the bar adjacent to the apex.

United States Patent [191 Heyek n11 3,871,080 1 Mar. 18, 1975 CUTTER FOILS FOR DRY SHAVING APPARATUS [75] inventor: Gerhard Heyek, Graz, Austria [73] Assignee: Famulus Elektrogerate Gesellschaft m.b.H., Graz, Austria 3,468,025 9/1969 Messinger 30/346.5l

Primary E.mnzinerAl Lawrence Smith I Assistant Examiner-Gary L. Smith Attorney, Agent, or Firm-Watson, Cole, Grindle and Watson [57] ABSTRACT A cutter foil for dry shaving apparatus, produced by electro-deposition, and comprising a main portion in which is an area of perforation and an edge zone joined to the main portion by a fold defining an apex extending longitudinally of the foil, a cutter comb constituted by bars extending across the apex and separated from each other by slots likewise extending across the apex, the breadths of the bars being greater than the breadths of the slots, and the bars containing perforations serving to enhance the thickness of the foil produced by electro-deposition in the region of the bars, the perforations in the bars being clear of a zone adjacent to the apex, whereby in each bar the foil is continuous across the width of the bar adjacent to the apex.

4 Claims, 4 Drawing Figures 1 CUTTER FOILS FOR DRY SHAVING APPARATUS The invention relates to perforated cutter foils for dry shaving apparatus, of the kind which are produced by electro-deposition, and which have at least one downwardly folded edge zone, and have in the neighbourhood of the apex of the fold a row of slots extending across this apex, which form a cutter comb for long hairs. In the electro-deposition operation, a matrix is first prepared, consisting of an electrically conductive plate, locally covered by insulating spots corresponding to openings required in the foil. These spots may for example be applied photographically. Then the metal to form the foil is deposited on the matrix by electrolysis.

Dry shaving apparatus, in which perforated cutter foils of this kind are used, are for example described in U.S. Pat. application Ser. No. 628,602 filed Apr. 5, 1967, now U.S. Pat. No. 3,436,822 and Ser. No. 70,084 filed Sept. 8, 1970, now U.S. Pat. No. 3,704,815.

If, in perforated cutter foils of the kind mentioned, the bars between the slots are very narrow, they have too little stiffness against loads arising in the direction along the apex of the fold of the cutter foil, i.e. in the direction of the cutting force, so that they easily tilt and can catch in the teeth of a cooperating lower cutter. There are, however, problems if the breadth of the bars is increased. With cutter foils produced by electrodeposition, the local foil thickness is larger, the smaller the bar surface per unit area. If there is a large proportion of bar surface in the cutter comb zone, the thickness of foil is so slight that the bars are insufficiently rigid against the pressing force during use of the dry shaving apparatus, and in addition, having regard to the wear by friction, have a significantly reduced working life.

The invention is concerned with the problem of avoiding the defects mentioned, i.e. with improving a perforated cutter foil of the kind mentioned initially in such a way that, with production by electro-deposition, it will have, in the zone of the cutter comb, an increased mechanical rigidity as compared with known constructions and also an increased resistance to wear. This is achieved in accordance with the invention in that the width of the bars present between adjacent slots is greater than the width of the slots, and that the bars are perforated while leaving a zone adjacent to the apex, whereby in each bar the foil is continuous across the width of the bar adjacent to the apex. By this means, the remaining bar surface is reduced relative to the area outlined by the bar, for the purpose of increasing the foil thickness produced in the cutter comb zone in production by electro-deposition.

The relatively great breadth of the perforated bars ensures, in the manner of a framework, a high resisting moment against loads in the direction of the cutting force. On the other hand, by the reduction of the remaining bar surface as a consequence of the perforation of the bars, an increased foil thickness is achieved in the cutter comb zone, and hence the rigidity of the bars against the pressing force during use of the dry shaving apparatus is increased, and so is the resistance of the bars to wear. The wide bars also hinder tilting of the latter relatively to the lower cutter and thus reduce the likelihood of break-down of the apparatus.

In a preferred form of construction of the invention the specific total hole area, i.e. the ratio of the total area of hole to the entire area, in the cutter comb zone is at least as great as in the area of perforation in the main portion, so that the foil thickness in the cutter comb zone produced by electro-deposition is at least as great as in the perforated cutter zone.

Further features and advantages of the invention appear from the following description of examples, with reference to the accompanying drawings.

In these drawings:

FIG. 1 shows schematically a cross section through a cutter head, in which can be used a perforated cutter foil with two cutter combs according to the invention;

FIG. 2 shows in perspective a part of the cutter head, broken away to show a cutter foil with a perforated cutter part as well as the lower cutter cooperating with these cutter parts, in which the comb cutter part of the cutter foil is formed in accordance with the prior art;

FIG. 3 shows in perspective a part of a cutter foil according to the invention as well as a part of the associated lower cutter; and

FIG. 4 shows in a similar perspective view another constructional form of the invention.

The cutter head frame 1 shown in FIGS. 1 and 2, is secured to the upper part of the housing (not shown) of the dry shaving apparatus. On the inner side of the frame are several inwardly directed noses 2, on which downwardly folded edge strips 4 of a cutter foil 3 are engaged by means of holes. In a convex upper part of the cutter foil there is the usual area of perforation 6 constituting a perforated cutter part, while in the neighbourhood of each of the apices 5 of the two folds in the cutter foil there are slots 7, which extend over these apices and alternate with bars 8, which form a cutter comb for long hairs.

In the interior of the cutter head frame 1 there is arranged a lower cutter unit, which, by means of known driving elements (not shown), is subjected to a reciprocating motion in a direction perpendicular to the plane of the drawing in FIG. 1, and is pressed resiliently by springs (not shown) into the concavity of the cutter foil In the example shown, the lower cutter unit consists of a frame 10, which has recesses 13 in its upper side, in which stamped out and inwardly bent tongues 12 of the lower cutter ll, likewise formed of metal foil, are so engaged that the lower cutter foil 11 assumes a curvature similar to that of the cutter foil 3. The central part of the lower cutter foil has long slots 14, which cooperate with the area of perforation 6 ofthe cutter foil 3 and form the shaving part of the apparatus.

At both lateral edges of the lower cutter foil 11, cutter teeth 15 are formed, which cooperate with the slots 7 and the bars 8 of the comb cutter parts of the cutter foil 3, and form so-called lateral cutters for long hairs at each side of the apparatus.

Each comb cutter part of the cutter foil 3 shown in FIG. 2 is of a known construction. It has slots 7 at the apex 5, which are completely separated from each other by relatively narrow bars 8.

In contrast, FIGS. 3 and 4 show comb cutter parts embodying the present invention. In these embodiments, in order to make the breadth B of the bars, measured in the direction along the apex 5, so large that tilting of the bars and catching with the teeth of the lower cutter foil 11 is no more to be feared, the breadth B of the bars 8 is chosen to be greater than the breadth b of the slots 7. On the other hand however, to achieve in production of the foil by electro-deposition a suffrcient foil thickness d in the zone of the comb cutter part, so as to achieve adequate rigidity and resistance to wear, the bar surfaces lying between adjacent slots are interrupted by perforations in such a way that in the production of the foil by electro-deposition a relatively large foil thickness is achieved in this zone. In FIG. 3 the perforations are elongated holes 19, which in FIG. 4 they are round holes 20.

In the FIGS. 3 and 4, the apex 5 of the fold in the cutter foil extends substantially centrally through bar zones 8a which extend over the entire bar breadth B, between the perforations in the bars 8. The breadth of the elongated holes 19 in FIG. 3, or the diameter of the circular holes 20 in FIG. 4, is advantageously chosen about equal to the breadth b of the slots 7 in the cutter comb zone.

The specific total hole area in the cutter comb zone,

the slots 7 and all the holes 19 or 20, to the total surface taken up by the sum of all slots 7 and all bars 8, is advantageously chosen to be at least as large as the specific total hole area in the perforated cutter zone, i.e. as the ratio ofthe surface taken up by the sum of all the holes in the varea of perforation 6, to the total area occupied by the area of perforation 6. In this way, during production of the cutter foil by electro-deposition, there is achieved in the cutter comb zone a foil thickness d which is at least substantially as large as in the perforated cutter zone.

Numerous variations are of course possible with reference to the form and arrangement of the holes in the bars of the comb cutter part, as well as with reference to the formation of the perforated cutter part of the cutter foil, and the formation of the lower cutter for the perforated and comb cutter parts.

I claim: 1. A cutter foil for dry shaving apparatus, produced by electro-deposition, and comprising a main portion in which is an area of perforation and an edge zone joined to the main portion by a fold defining an apex extending longitudinally of the foil, a plurality of slots extending across the apex, a cutter comb constituted by bars extending across the apex and each defined by a respective portion of the foil extending between adjacent slots, the breadths of the bars being greater than the breadths of the slots, and the bars containing perforations located primarily in the area extending between the slots, which area is bounded by the upper and lower extents of the slots, said perforations serving to enhance the thickness of the foil produced by electrodeposition in the region of the bars, the perforations in the bars being clear of a zone adjacent to the apex, whereby in each bar the foil is continuous across the width of the bar adjacent to the apex.

2. A cutter foil according to claim 1, wherein the specific total hole area in the cutter comb is at least as great as in the area of perforation in the main portion.

3. A cutter foil according to claim 1, wherein the apex runs substantially centrally through the zone in which the foil is continuous across the width of the bars and the apex extends between at least two rows of perforations in the bars on opposite sides thereof.

4. A cutter foil according to claim 1, wherein the perforations of the bars have a dimension inthe direction of the breadth of the bars substantially equal to the breadth of the slots. 

1. A cutter foil for dry shaving apparatus, produced by electrodeposition, and comprising a main portion in which is an area of perforation and an edge zone joined to the main portion by a fold defining an apex extending longitudinally of the foil, a plurality of slots extending across the apex, a cutter comb constituted by bars extending across the apex and each defined by a respective portion of the foil extending between adjacent slots, the breadths of the bars being greater than the breadths of the slots, and the bars containing perforations located primarily in the area extending between the slots, which area is bounded by the upper and lower extents of the slots, said perforations serving to enhance the thickness of the foil produced by electro-deposition in the region of the bars, the perforations in the bars being clear of a zone adjacent to the apex, whereby in each bar the foil is continuous across the width of the bar adjacent to the apex.
 2. A cutter foil according to claim 1, wherein the specific total hole area in the cutter comb is at least as great as in the area of perforation in the main portion.
 3. A cutter foil according to claim 1, wherein the apex runs substantially centrally through the zone in which the foil is continuous across the width of the bars and the apex extends between at least two rows of perforations in the bars on opposite sides thereof.
 4. A cutter foil according to claim 1, wherein the perforations of the bars have a dimension in the direction of the breadth of the bars substantially equal to the breadth of the slots. 